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Review: Asus X99-A

by Tarinder Sandhu on 19 December 2014, 11:06

Tags: Intel (NASDAQ:INTC), ASUSTeK (TPE:2357)

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It is customary for Intel to release a trio of processors for the ultra-high-end PC desktop market. The Sandy Bridge, Ivy Bridge and Haswell architectures have all been recipients of the 'Extreme' makeover in recent years. This time around, the Haswell iteration debuts with DDR4 memory and more cores and threads than ever before.

What makes this recent launch all the more interesting is the fact that the cheapest Haswell Extreme CPU, Core i7-5820K, is largely the same as the mid-pack Core i7-5930K. Both share the same six cores and 12 threads, increase frequency to almost the same levels, and are only differentiated, in a meaningful sense, by a difference in PCIe lanes - 28 vs. 40.

Such commonality is a boon for the enthusiast looking for premium performance on the relatively cheap. Said Core i7-5820K is priced at at around £300, so the next part of the value-for-money jigsaw rests with motherboard and DDR4 vendors. Top-tier motherboard manufacturers have realised the sales potential of pairing a value-focussed X99 board with the Core i7-5820K, leading to a number of boards priced at well below £200.

Asus comes armed to this budget Haswell-E party with the X99-A, widely available for £190. Let's take a closer look.

The A variant sits below the S, Pro, and Deluxe in Asus' regular line-up. The Taiwanese giant prefers to keep certain features rather than reduce the price further. At £190 or so, the X99-A remains significantly more expensive than the MSI X99-Plus (£155) or Gigabyte X99-UD3 (£160).

But for this extra outlay Asus provides three-way AMD CrossFire and Nvidia SLI support as standard. Other goodies include SATA Express by way of the X99 chipset, upgraded sound, onboard activity buttons, full-bandwidth M.2 support, and a solid BIOS. And there's the OC Socket, of course, offering class-leading overclocking capabilities for the CPU and memory. Perhaps the better comparison is with the Asus X99-S, which provides extra SATA Express and Deluxe-like cooling for an additional £25.

Good component location enables the full complement of eight DDR4 slots to be positioned a reasonable distance away from the large socket. We had no problem in installing a Noctua DH15 cooler in a sideways orientation, leaving adequate space for a necessary graphics card in the first PCIe x16 slot.

It would be excusable for Asus to take the Deluxe version and trim away features in order to hit a lower price point. We know this hasn't happened because the PCB is different; one example of which is the relocation of the M.2 slot just below the southbridge. Now horizontal rather than vertical, there's enough space to house full-length modules between the board's two bottom-located PCIe x16.

And while the PCB has room for four mechanical PCIe x16 arranged in conventional manner, perusal of the manual shows that the second slot grabs its bandwidth from the chipset, not the CPU. The upshot is that X99-A is 'limited' to three cards for multi-GPU usage.

Storage support comes by way of a PCIe x4 interface for the M.2 connected to the CPU, rather than riding on the same bandwidth as other storage; great for super-fast speeds. Be aware that hooking right into the CPU means that the third PCIe x16 slot cannot be used concurrently - there is simply not enough chipset connectivity, even on a 40-lane CPU, for all peripherals to be connected at once. Some boards sacrifice SATA for M.2 by using the same shared connection; others, like Asus and ASRock, reckon direct-CPU connection is the way to go.

Regular SATA, meanwhile, is represented by 10 ports, of which two can be pressganged into SATA Express service. Intel's configuration is such that six out of the 10 gain Rapid Storage Technology support, meaning the other four cannot be part of the same Intel-controlled RAID setup.

A lack of an auxillary ASMedia USB3.0 controller, as found on the Deluxe, drops the number of available ports from 10 to six. This more basic model also foregoes a second Gigabit LAN and the Bluetooth and WiFi goodness of its bigger brother. Such sacrifices seem sensible when opting for a lower price point.